Microsporidia in fish

Abstract

The importance of microsporidia in captive fishes continues to increase with the continued dramatic increase in finfish aquaculture. Most microsporidia of fish are transmitted without intermediate hosts, and hence, cultured fish are particularly susceptible to microsporidian infections due to high stocking densities, compared to their wild counterparts. There are several examples of microsporidia causing disease in cultured food fishes. Early investigations of fish microsporidia included some observations of host response. Several drugs have been used to treat microsporidian infections in fish, mostly on an experimental basis. Most reports of successful treatments were with fumagillin. This drug is an antimicrobial agent developed for treating Nosema apis infections in honeybees and is the most widely used drug used for treating microsporidiosis in fishes.